Wolfe, Gordon W wrote:
He used ssh because it was "more secure" and compressed it to "save bandwidth".
> This even though all the communications took place internally to CP > (VCTCA links) and never even hit an ethernet cable. This would be REAL hard > to put a sniffer on!
Don't forget authentication. Even though you don't care who sees the data (because it is public) you may still want to make sure who puts it there. You cannot blame people who are used to have dedicated hardware. The SSH folks will tell you not to worry about the cost because 'modern CPUs are fast enough to keep up with network speed' Maybe for 100 Mb/s ethernet and a 2.8 GHz Pentium. But not for Gigabit Ethernet or faster, and a slow z800 engine. And when others can use the CPU while you wait for the network traffic, then things are really different.
He called wondering why his bill was so big. He wondered if it was that three-hour
> copy job he did. I told him he saved bandwidth by exchanging it for > CPU cycles for the compression and encryption and he was paying for those CPU > cycles. I also told him I could have copied the entire disk using > snapshot in about 10 seconds at no cost to him. But using snapshot is kind of cheating... We also noticed at a customer they were copying SuSE ISO images over from one system to the other through a shared OSA card. It ran at 1 MB/s and burned a z900 engines on both sides. Simply picking a 'less secure' cipher in SSH (e.g. -c blowfish) gives you 3-4 times as much throughput. And using 'rsh' instead got us 2 orders of magnitude faster. Rob
